Interesting, thanks for this. Our 2013 Forester is loud at highway speeds - to the point where I've been thinking about buying something different. The Forester is otherwise just fine.It’s put under the existing surfaces on bare metal; remove the carpet or mats and apply foil face up. The back side is self adhesive. Doors would be more labor intensive as you’d have to remove the inner door panels, window glass and mechanisms. Doing the floors will be the most effective.